Question

The instruction, Add #45,R1 does _______

(a) Adds the value of 45 to the address of R1 and stores 45 in that address

(b) Adds 45 to the value of R1 and stores it in R1

(c) Finds the memory location 45 and adds that content to that of R1

(d) None of the mentioned

This question was addressed to me in semester exam.

My question is taken from Addressing Modes in portion Machine Instructions and Programs of Computer Architecture

Answer 1

Right option is (b) Adds 45 to the value of R1 and stores it in R1

Explanation: The instruction is using immediate addressing mode hence the value is stored in the location 45 is added.